Analyses of jaw movement(obtained by Electromagnetic Articulography) and acoustics show that loud speech is an intricate phenomenon. Besides involving higher intensity and subglottal pressure it affects jaw movements as well as fundamental frequency and especially first formants. It is argued that all these effects serve the purpose of enhancing perceptual salience

Geumann, Anja

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70Vocal intensity: acoustic and articulatory correlatesAnja GEUMANNInstitut für Phonetik und Sprachliche Kommunikation,Ludwig-Maximilians-Universität Munich, Schellingstr. 3/II. VG, 80799 Munich, Germanygeumann@phonetik.uni-muenchen.deAbstract. Analyses of jaw movement (obtained by Electromagnetic Articulography) and acoustics show thatloud speech is an intricate phenomenon. Besides involving higher intensity and subglottal pressure it affectsjaw movements as well as fundamental frequency and especially first formants. It is argued that all theseeffects serve the purpose of enhancing perceptual salience.1. IntroductionIn earlier work vocal intensity was primarily investigated in its relation to sound pressure or aerodynamicconditions below or around the glottis (e.g. Ladefoged/McKinney 1963, Holmberg et al. 1988). More recentexperiments also indicate that changes in vocal intensity are coupled with changes in articulatory dynamicswithin the vocal tract (Schulman 1989, Dromey et al. 1995, Geumann et al. 1999).Ladefoged/McKinney (p. 460) described the way the listener identifies loudness in the following way: "It isof course probably true, that what the listeners were doing when they were judging the loudnesses [...] wasassessing the amount of effort they themselves would have to make in order to produce corresponding sounds."Here we would like to present articulatory and acoustic data that show that speakers indeed modify theirarticulatory dynamics according to intended volume level. Thus, the assumption that loudness for the speaker isdirectly related to physiological effort will be further supported.2. ExperimentKinematic and acoustic recordings were made of read phrases, produced by 6 German speakers (one female,five male). Pseudo-word 'VCV sequences were embedded in carrier phrases of the type "Hab das Verb ___ mitdem Verb ___ verwechselt". Data for some of the speakers were presented in Geumann et al. (1999).The consonants were the alveolar German phonemes differing in manner of articulation /s, S, l, n, d, t/ (/S/is postalveolar). They were placed in differing symmetric vowel height contexts /i__i, e__e, a__a/; both vowelswere long, with main stress on the first vowel. All phrases were produced in loud and normal speech, whichwas elicited by simple instruction of the speaker. The loud and normal phrases were presented in random order.For each target consonant with given loudness and vowel context 12 repetitions were produced, totalling 72repetitions of each consonant over all context and loudness conditions.The two-dimensional (midsagittal) kinematic signals were recorded with an electromagnetic transductionsystem (Articulograph AG100, Carstens Medizinelektronik, for more technical details see Hoole 1996). Foursensors were placed on the tongue, three sensors were used to track jaw movement. One was placed on each ofinner and outer surface of the gums beneath the lower incisors, a third sensor was placed on the angle of thechin. Reference sensors were located on upper jaw and the nasion. Jaw movement was corrected for headmovement and postprocessed data were rotated, so that the x-axis is parallel to the occlusal plane, with theorigin at the position of the reference coil above the upper incisors. Only data of the outer jaw sensor will beconsidered below.Simultaneously, acoustic data were recorded with a Sennheiser MK H20 P48 microphone (preamplifierhigain 44) approx. 30cm distant to the speaker’s mouth. Data were stored on a Sony PC 208Ax DAT-recorder,sampling rate of the data was 24kHz/16bit. Additionally, speakers were recorded frontally on video.Further analysis of the articulatory data was performed with Matlab (using macros written by Phil Hoole).Manually selected minimal jaw position within the acoustic vowel (V1) segment was considered as vowel targetposition, absolute maximal jaw position following the minimal peak was identified as consonantal targetposition, following absolute minimal jaw position was considered as V2 target position. Analysis of the acousticdata was performed using the praat program package developed by Paul Boersma and David Weenink.Fundamental frequency and formants were extracted automatically, with some post editing.3. ResultsData in Figure 1 indicate that in loud voice condition all speakers effectively produced vowels (as well asPublished in: Maassen, B. et. al. (eds.): Speech Motor Control in Normal and Disordered Speech. Proceedings of the 4th International Speech Motor Conference. Nijmegen: Uitgeverij Vantilt, 2001. p. 70-73. 71consonants) with higher intensity. However, it has been noted by Eriksson/Traunmüller (1999) andWilkens/Bartel (1977) that listeners can estimate or reconstruct the speaker’s loudness independently of theperceived sound pressure level.Data in Figure 2 and 3 demonstrate that all speakers show a more open jaw position in loud voice condition invowels, whereas, during coronal consonant production loud voice condition has no effect on jaw position inmost speakers. It is discussed elsewhere (e.g. Shadle 1985, 1990, Lee et al. 1994, Narayanan 1995 Geumann etal. 1999, Geumann in prep.) that the jaw, carrying the lower incisors, plays an important role in the productionof strident fricatives /s/ and /S/. Either way jaw movements are found to be larger in loud speech.The acoustic data exhibit a modified durational pattern with loud voice, with vowels lengthened and consonantsshortened, which was stated for French data as well (Bonnot/Chevrie-Muller 1991). Besides, a rather strongeffect on fundamental frequency and first formant has been found (see as well Traunmüller/Eriksson 2000). Inloud voice condition, fundamental frequency is considerably higher (Figure 4) as is the first formant (Figure 5).Effects on second formant value (Figure 6) were noted mainly for /a:/, which is a non-front vowel in German.The third formant values (Figure 7) are in loud voice condition centralized towards a focus around 2600Hz.Vowel intensitySPEAKERSpeaker ur (m)Speaker sr (m)Speaker rs (m)Speaker kh (m)Speaker hp (m)Speaker aw (f)807876747270686664VOLloud voicemodal voiceFigure 1. Intensity (in dB) of vowel segments (V1 and V2).T-test was performed and revealed a highly significant effectof volume level for all speakers. n = max. 432.Speakerur (m)sr (m)rs (m)kh (m)hp (m)aw (f)-.4-.6-.8-1.0-1.2-1.4-1.6-1.8-2.0VolumeLNFigure 2. Jaw height (in cm) at consonantal target positionfor loud vs. modal voice. An independent samples t-test wasperformed and showed for speaker ur (p<0.001) and kh(p<0.01) a highly significant effect of volume level, for otherfour speakers no significant effect. n = max. 216.Speakerur (m)sr (m)rs (m)kh (m)hp (m)aw (f)0.0-.5-1.0-1.5-2.0-2.5-3.0VolumeLNFigure 3. Jaw height (in cm) at stressed vowel (V1) targetposition for loud vs. modal voice. An independent samples t-test was performed and showed a highly significant effect(p<0.001) of volume level for all speakers. n = max. 216.Over all vowels f0 means for individual speakersSpeakerur (m)sr (m)rs (m)kh (m)hp (m)aw (f)ean f0 in Hz300200100Volumemodal voiceloud voiceFigure 4. Effect of volume level on mean fundamentalfrequency (in Hz) in long vowels for individual speakers.Independent t-test comparison of means showed that effectof volume level is highly significant (p<0.001) for allspeakers. n = max. 432.72All speakers - F1target vowela:e:i:800700600500400300200Volumemodal voiceloud voiceFigure 5. Effect of volume level on first formant. Data in Hzpooled for all speakers and for V1 and V2. An independentsamples t-test was performed and showed a highlysignificant effect of volume level on F1 (p<0.001) for allvowels. n = max. 880.All speakers - F2target vowela:e:i:24002200200018001600140012001000Volumemodal voiceloud voiceFigure 6. Effect of volume level on second formant. Data inHz pooled for all speakers and for V1 and V2. Anindependent samples t-test was performed and showed ahighly significant effect of volume level on F2 (p<0.001) for/a:/, significant effect (p<0.05) on /i:/, no significant effecton /e:/. n = max. 880.All speakers - F3target vowela:e:i:310030002900280027002600250024002300Volumemodal voiceloud voiceFigure 7. Effect of volume level on third formant. Data in Hzpooled for all speakers and for V1 and V2. An independentsamples t-test was performed and showed a highlysignificant effect of volume level on F3. For /a:/ and /i:/p<0.001, for /e:/ p<0.01. n = max. 880.4. ConclusionArticulatory and acoustic modification found with loud voice can be interpreted as an amplification of jawmovement, which might additionally help to shift acoustic durational patterns towards longer (more intense)vowels and shorter (in general less intense) consonants. Changes in fundamental frequency and first formantare easily explained by perceptive demands. A higher fundamental frequency is perceived more intense, andperception of vowel height refers to the difference between first formant and fundamental frequency(Syrdal/Gopal 1986). Raising of fundamental frequency therefore demands a higher first formant if vowelquality is to be preserved. On the other hand a higher first formant can be interpreted as resulting from a lowerjaw position.In addition, it was found that overall jaw activity can be quite different across speakers (see as wellHertrich/Ackermann 2000). Comparison of amplitudes of jaw and intrinsic tongue tip movements in consonantproduction revealed generally a higher jaw activity for speaker sr. Conversely, speaker ur only showed acomparatively small amount of overall jaw activity. In short, patterns of jaw activity can differ considerablyacross speakers.To sum up, the phenomenon of loud speech can be said to be constituted by a varied collection ofinterdependent articulatory and acoustic parameters.73AcknowledgementsThis work was partially supported by the German Research Council (DFG) (Ti69/31).ReferencesBonnot, J.-F. P., Chevrie-Muller, C. (1991) Some effects of shouted and whispered conditions on temporal organization. J.Phonetics 19, 473-483.Dromey, C., Ramig L.O., Johnson, A.B. (1995) Phonatory and articulatory changes associated with increased vocalintensity in Parkinson disease: a case study. Journal of Speech and Hearing Research, 38, 751-764.Eriksson, A., Traunmüller, H. (1999) Perception of vocal effort and speaker distance on the basis of vowel utterances.Proceedings of the 14th International Congress of Phonetic Sciences (ICPhS), San Francisco, 3, 2469-2472.Geumann, A. (in prep.) Invariance and variability in articulation and acoustics of natural perturbed speech. Ph. Diss.University of Munich.Geumann, A., Kroos, C., Tillmann, H.G. (1999) Are there compensatory effects in natural speech? Proc. 14th InternationalCongress of Phonetic Sciences 1999. San Francisco, August, 399-402.Hertrich, I., Ackermann, H. (2000) Lip-jaw and tongue-jaw coordination during rate-controlled syllable repetitions. Journalof the Acoustical Society of America 107(4), 2236-2247.Holmberg, E.B., Hillman, R.E., Perkell, J.S. (1988) Glottal airflow and transglottal air pressure measurements for maleand female seakers in soft, normal, and loud voice. Journal of the Acoustical Society of America 84(2), 511-529.Hoole, P. (1996) Issues in the acquisition, processing, reduction and parameterization of articulographic data,Forschungsberichte des Instituts für Phonetik und Sprachliche Kommunikation, München (FIPKM) 34, 158-173.Ladefoged, P. (1990) On dividing phonetics and phonology: comments on the papers by Clements and by Browman andGoldstein. In: J. Kingston & M. Beckman (Eds.) Papers in Laboratory Phonology 1, Cambridge: Cambridge UniversityPress, 398-405.Ladefoged, P., McKinney, N.P. (1963) Loudness, sound pressure, and subglottal pressure in speech. Journal of theAcoustical Society of America 35, 454-460.Lee, S., Beckman, M., Jackson, M. (1994) Jaw targets for strident fricatives. Proc. of the International Conference onSpoken Language Processing (ICSLP) 1994 Yokohama, 37-40.Narayanan, S.S. (1995) Fricative consonants: An articulatory, acoustic, and systems study. PhDiss. UCLA.Praat [On-line]: Information at: http://www.fon.hum.uva.nl/praat/Schulman, R. (1989). Articulatory dynamics of loud and normal speech. Journal of the Acoustical Society of America 85,295-312.Shadle, C.H. (1985) The acoustics of fricative consonants. Ph.D. thesis, MIT.Shadle, C.H. (1990) Articulatory-acoustic relationships in fricative consonants. In: W. Hardcastle & A. Marchal (eds.),Speech Production and Speech Modelling. Dordrecht: Kluwer Academic Publishers, 187-209.Syrdal, A.K., Gopal, H.S. (1986) A perceptual model of vowel recognition based on the auditory representation ofAmerican English vowels. Journal of the Acoustical Society of America 79(4), 1086-1100.Traunmüller, H., Eriksson, A. (2000) Acoustic effects of variation in vocal effort by men, women, and children. Journal ofthe Acoustical Society of America 107(6), 3438-3451.Wilkens, H., Bartel, H.-H. (1977) Wiedererkennbarkeit der Originallautstärke eines Sprechers bei elektroakustischerWiedergabe. Acustica 37, 45-49.

Vocal intensity: acoustic and articulatory correlates

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Vocal intensity: acoustic and articulatory correlates

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